<!DOCTYPE html>
<html>

<head>
    <title>js test</title>
    <meta charset="utf-8">
    <script type="text/javascript">
    	function setCookie(cname, cvalue, exdays){
    		var d = new Date();
    		d.setTime(d.getTime()+(exdays*24*60*60*1000));
    		var expires = "expires=" + d.toGMTString();
    		document.cookie = cname + "=" + cvalue + "; " + expires;
    	}
    	function getCookie(cname){
    		var name = cname + "=";
    		var ca = document.cookie.split(';');
    		for (var i=0; i<ca.length; i++){
    			var c = ca[i].trim();
    			if (c.indexOf(name)==0) return c.substring(name.length, c.length);
    		}
    		return "";
    	}
    	function checkCookie(){
    		var user = getCookie("username");
    		if (user!=""){
    			alert("Welcome again " + user);
    		}
    		else{
    			user = prompt("Please enter your name:","");
    			if (user!="" && user!=null){
    				setCookie("username", user, 30);
    			}
    		}
    	}
    </script>

</head>

<body onload="checkCookie()">
	
	
	
</body>

</html>